Biological Control of Insect Pests Using Bacillus thuringiensis

Bacillus thuringiensis (Bt) is a Gram-positive, spore-forming bacterium that produces a range of proteinaceous toxins active against insect larvae. The primary insecticidal agents are crystalline δ-endotoxins (Cry proteins) and cytolytic Cyt proteins, which are deployed both as sprayable formulations and within transgenic crops. Upon ingestion by susceptible insects, these proteins are solubilised in the alkaline midgut, proteolytically activated and bind to specific receptors on epithelial cells, causing pore formation, cell lysis and insect mortality. Bt formulations and Bt-expressing crops have become cornerstone tools in integrated pest management, offering high specificity, environmental safety and reduced reliance on chemical insecticides. However, the widespread use of Bt has led to the emergence of resistant pest populations, stimulating research into resistance mechanisms, novel toxin variants and complementary ecological strategies. Advances include the discovery of new Bt strains with improved toxin spectra, elucidation of key receptor interactions, and integration of landscape heterogeneity to slow resistance evolution. Collectively, these efforts aim to sustain the efficacy of Bt-based control worldwide, from agriculture to vector management.

Research from Nature Portfolio

Recent studies have demonstrated the potential of novel Bt strains for targeted pest control. A bespoke Bt strain with enhanced toxicity against the greater wax moth achieved a median lethal concentration (LC50) below 2 μg/g for larvae, while exhibiting minimal toxicity to honey bees. Researchers integrated this strain into an entrapment device combining a species-specific lure and barrier system that prevented non-target exposure. Laboratory and field trials confirmed significant reductions in pest populations within apiaries, illustrating the practicality of combining microbial bioinsecticides with physical trapping to protect pollinators and enhance hive health.

Biological Control of Insect Pests Using Bacillus thuringiensis publication trend

The graph below shows the total number of articles in biological control of insect pests using bacillus thuringiensis across all publications each year (not limited to Nature Index journals).

Technical terms

Cry proteins: Insecticidal crystal δ-endotoxins produced by B. thuringiensis that form pores in midgut epithelial cells of target insects.

LC50: The concentration of a substance required to kill 50 per cent of a test population under defined conditions.

Transgenic crops: Plants genetically engineered to express Bt toxin genes, conferring resistance to specific insect pests.

Glycoconjugate receptor: Carbohydrate-containing proteins or lipids on insect midgut cells that serve as binding sites for Bt toxins.

m6A RNA methylation: A reversible post-transcriptional modification of messenger RNA that influences gene expression and can affect insect hormone regulation.

Juvenile hormone: An insect endocrine signal that controls development, reproduction and physiological trade-offs during immune defence.

Ecological heterogeneity: Variation in environmental conditions or pest management practices that creates diverse selection pressures on pest populations.

References

1. Bacillus thuringiensis Toxins: An Overview of Their Biocidal Activity. Toxins (2014).
2. Greater wax moth control in apiaries can be improved by combining Bacillus thuringiensis and entrapments. Nature Communications (2023).
3. The role of glycoconjugates as receptors for insecticidal proteins. FEMS Microbiology Reviews (2023).
4. RNA m6A Methylation Suppresses Insect Juvenile Hormone Degradation to Minimize Fitness Costs in Response to A Pathogenic Attack. Advanced Science (2023).
5. Increasing ecological heterogeneity can constrain biopesticide resistance evolution. Trends in Ecology & Evolution (2023).